Function `not`

fn not<I: Clone, E: ParseError<I>, F>(parser: F) -> impl Parser<I, Output = (), Error = E>
where
    F: Parser<I, Error = E>

Succeeds if the child parser returns an error.

# use nom::{Err,error::ErrorKind, IResult, Parser};
use nom::combinator::not;
use nom::character::complete::alpha1;
# fn main() {

let mut parser = not(alpha1);

assert_eq!(parser.parse("123"), Ok(("123", ())));
assert_eq!(parser.parse("abcd"), Err(Err::Error(("abcd", ErrorKind::Not))));
# }